HARQ-ACK Codebook Bundling for Postponed 5G NR-U Feedback

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Solution Overview

Problem

The challenge of determining semi-static HARQ-ACK codebooks for frame-based equipment (FBE) operation in 3GPP 5G NR-U has not been adequately addressed, leading to potential misunderstandings between user equipment (UE) and base stations regarding HARQ-ACK feedback timing and increased transmission losses due to postponed feedback.

Innovation Solution

A method and apparatus for determining HARQ-ACK codebooks that include both current and postponed HARQ-ACK feedback by configuring multiple K1 sets for intra- and cross-FFP transmissions, using DCI indicators to signal timing offsets and HARQ-ACK bundling, ensuring synchronized HARQ-ACK codebook understanding between UE and BS.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If HARQ-ACK feedback is postponed to the next periodic channel occupancy, then transmission timing flexibility is improved, but feedback delay increases and transmission losses occur

Engineering Contradiction:

Improvetransmission timing flexibilityVSAvoidfeedback delay

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the UE prepare and buffer HARQ-ACK feedback information in advance when downlink data is received in one periodic channel occupancy, then transmitting this pre-prepared feedback in the next periodic channel occupancy. This allows the feedback to be ready beforehand, reducing actual transmission delay while maintaining timing flexibility.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamics by allowing the HARQ-ACK codebook to be dynamically constructed based on whether feedback needs to be postponed. The codebook structure adapts between containing only current periodic feedback or including both current and postponed feedback from earlier periods, providing flexible timing adaptation without fixed delay.

Inventive Principle:

Principle #15Dynamics

2Reliability

If HARQ-ACK codebook includes both current and postponed feedback, then feedback completeness is improved, but codebook size and processing complexity increase

Engineering Contradiction:

Improvefeedback completenessVSAvoidcodebook processing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the HARQ-ACK codebook into distinct portions: current periodic feedback and postponed feedback from earlier periods. This segmentation allows the UE and gNB to clearly identify and process different feedback components separately, reducing confusion and processing complexity while ensuring complete feedback transmission.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements feedback mechanisms where the gNB sends DCI indicators to inform the UE about codebook type (including postponed feedback or not), and the UE accordingly adjusts its codebook construction. This feedback loop ensures both sides maintain consistent understanding of codebook contents, reducing processing complexity through clear signaling.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If multiple K1 sets are configured for intra- and cross-FFP transmissions, then HARQ-ACK timing flexibility is improved, but signaling overhead increases

Engineering Contradiction:

ImproveHARQ-ACK timing flexibilityVSAvoidsignaling overhead

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent applies partial action by configuring multiple K1 sets but only activating or using the necessary subset for specific transmission scenarios. Not all K1 sets need to be utilized in every transmission, allowing timing flexibility when needed while avoiding unnecessary signaling overhead when standard timing suffices.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent implements parameter changes by using different K1 values from the configured sets to adjust HARQ-ACK timing parameters based on transmission conditions. The system can switch between different K1 sets to optimize timing for intra-FFP versus cross-FFP transmissions, providing flexibility through parameter selection rather than fixed configuration.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12376119B2Method and apparatus for HARQ-ACK codebook determination for frame-based equipment operation

Publication Date: 2025.07.29 LENOVO (BEIJING) LTD

AI summary

The present application is related to a method and apparatus for semi-static hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook determination for FBE operation under 3GPP 5G new radio (NR). A method for wireless communications performed by a UE includes: receiving downlink control information (DCI) for scheduling a data transmission in a current periodic channel occupancy; determining whether there is HARQ-ACK feedback corresponding to a data transmission postponed in an earlier periodic channel occupancy; and transmitting a HARQ-ACK codebook in the current periodic channel occupancy, wherein, in response to determining that there is the HARQ-ACK feedback corresponding to the data transmission postponed in the earlier periodic channel occupancy, the HARQ-ACK codebook comprises HARQ-ACK feedback corresponding to the data transmission in the current periodic channel occupancy and the postponed HARQ-ACK feedback corresponding to the data transmission in the earlier periodic channel occupancy.